About the presence of Megalastrum substrigosum (Dryopteridaceae) in Argentina

En este trabajo se cita por primera vez a Megalastrum substrigosum para Argentina, en el departamento de San Pedro, provincia de Misiones. Se presenta una descripción general de la especie, el mapa de su distribución en el país e ilustraciones sobre los caracteres más importantes para su determinación. Se incluye una clave dicotómica para diferenciar las tres especies presentes en Misiones.About the presence of Megalastrum substrigosum (Dryopteridaceae) in Argentina. This paper presents the first record of Megalastrum substrigosum from Argentina, in Department San Pedro, Misiones province. We present a description of the species, a distribution map, and illustrations of the diagnostic characters. A dichotomous key is included to differentiate the three Megalastrum species from Misiones.Facultad de Ciencias Naturales y Muse

Ferns and Lycophytes from Yabotí Biosphere Reserve, Misiones, Argentina: Parque Provincial Moconá

El Parque Provincial Moconá se encuentra situado en el extremo este de la provincia de Misiones (Argentina), circundado por los ríos Yabotí y Uruguay. Pertenece a la Reserva de la Biosfera Yabotí y, en conjunto con otras áreas protegidas dentro de la Reserva Yabotí, representa uno de los principales relictos de selva paranaense del país. En el presente trabajo se llevó a cabo un relevamiento exhaustivo de las especies de helechos y licofitas que crecen en el parque. Se realizaron viajes de recolección al área de estudio y se consultaron los herbarios nacionales. Se hallaron 71 taxones de los cuales 38 representaron nuevos registros para el área protegida. Se provee una clave para el reconocimiento de los taxones y se realizan consideraciones respecto a su hábitat. Adicionalmente se discute su relación con el Parque Estadual do Turvo, Rio Grande do Sul (Brasil) con el cual limita, y la relevancia respecto a la conservación de la flora nativa.The Parque Provincial Moconá is in the east of the Misiones province, surrounded by Yabotí and Uruguay rivers. It belongs to Yabotí Biosphere Reserve, and together with other Biosphere’s protected areas, it represents one of the main relicts of the Paranaense forest in the country. In this work, fern and lycophyte species that grow in the park were exhaustively surveyed. Field trips were carried out to the study area and national herbaria were consulted. Seventy-one taxa were found, 38 of which represent new records for the protected area. A comprehensive key to the species and habitat considerations are provided. Additionally, the relationship with the adjacent protected area Parque Estadual do Turvo, Rio Grande do Sul (Brazil) and the relevance to the conservation of native flora is discussed.Instituto de Fisiología VegetalFacultad de Ciencias Naturales y MuseoConsejo Nacional de Investigaciones Científicas y Técnica

Plasticity of root growth and respiratory activity: Root responses to above-ground senescence, fruit removal or partial root pruning in soybean

This work focuses on the alterations in soybean root growth and activity during whole plant senescence and the contribution of roots to source-sink relations during plant development. The experiments were designed to analyze the activity of roots in relation to: a) whole plant senescence, b) total pod removal and c) root pruning (15, 25 and 50% of DW) during seed growth stages. Roots can grow until an advanced R5 stage and their specific activity decreases along the reproductive development but whole root activity declines from R6. However root respiration is maintained at a basal level until R8. Depodded plants showed a large increase of root dry matter (about 470%) and a large increase of AOX protein. Root pruning treatments showed a proportional increase of specific root respiration in 25 and 50% treatments but no differences of whole root respiration and dry matter partitioning at R7. These results indicate that roots are under the control of the requirements of above ground organs until final stages of seed growth but, after this, roots may survive independently for some time. This suggests that roots do not suffer a senescence-like process as leaves do. Also, plants have a high capacity to buffer changes in root biomass production and specific root activity under pod removal or partial root pruning.Instituto de Fisiología Vegeta

WHOI Hawaii Ocean Timeseries Station (WHOTS): WHOTS-11 2014 mooring Turnaround Cruise Report

The Woods Hole Oceanographic Institution (WHOI) Hawaii Ocean Timeseries Site (WHOTS), 100 km north of Oahu, Hawaii, is intended to provide long-term, high-quality air-sea fluxes as a part of the NOAA Climate Observation Program. The WHOTS mooring also serves as a coordinated part of the Hawaii Ocean Timeseries (HOT) program, contributing to the goals of observing heat, fresh water and chemical fluxes at a site representative of the oligotrophic North Pacific Ocean. The approach is to maintain a surface mooring outfitted for meteorological and oceanographic measurements at a site near 22.75°N, 158°W by successive mooring turnarounds. These observations will be used to investigate air–sea interaction processes related to climate variability. This report documents recovery of the tenth WHOTS mooring (WHOTS-10) and deployment of the eleventh mooring (WHOTS-11). Both moorings used Surlyn foam buoys as the surface element and were outfitted with two Air–Sea Interaction Meteorology (ASIMET) systems. Each ASIMET system measures, records, and transmits via Argos satellite the surface meteorological variables necessary to compute air–sea fluxes of heat, moisture and momentum. The upper 155 m of the moorings were outfitted with oceanographic sensors for the measurement of temperature, conductivity and velocity in a cooperative effort with R. Lukas of the University of Hawaii. A pCO2 system and ancillary sensors were installed on the buoys in cooperation with Chris Sabine at the Pacific Marine Environmental Laboratory. A set of radiometers were installed in cooperation with Sam Laney at WHOI. The WHOTS mooring turnaround was done on the NOAA ship Hi’ialakai by the Upper Ocean Processes Group of the Woods Hole Oceanographic Institution. The cruise took place between 15 and 23 July 2014. Operations began with deployment of the WHOTS-11 mooring on 16 July. This was followed by meteorological intercomparisons and CTDs. Recovery of the WHOTS-10 mooring took place on 20 July. This report describes these cruise operations, as well as some of the in-port operations and pre-cruise buoy preparations.Funding was provided by the National Oceanic and Atmospheric Administration under Grant No. NA140AR4320158 and the Cooperative Institute for the North Atlantic Region (CINAR

Evolution of structural diversity of trichothecenes, a family of toxins produced by plant pathogenic and entomopathogenic fungi

[EN] Trichothecenes are a family of terpenoid toxins produced by multiple genera of fungi, including plant and insect pathogens. Some trichothecenes produced by the fungus Fusarium are among the mycotoxins of greatest concern to food and feed safety because of their toxicity and frequent occurrence in cereal crops, and trichothecene production contributes to pathogenesis of some Fusarium species on plants. Collectively, fungi produce over 150 trichothecene analogs: i.e., molecules that share the same core structure but differ in patterns of substituents attached to the core structure. Here, we carried out genomic, phylogenetic, gene-function, and analytical chemistry studies of strains from nine fungal genera to identify genetic variation responsible for trichothecene structural diversity and to gain insight into evolutionary processes that have contributed to the variation. The results indicate that structural diversity has resulted from gain, loss, and functional changes of trichothecene biosynthetic (TRI) genes. The results also indicate that the presence of some substituents has arisen independently in different fungi by gain of different genes with the same function. Variation in TRI gene duplication and number of TRI loci was also observed among the fungi examined, but there was no evidence that such genetic differences have contributed to trichothecene structural variation. We also inferred ancestral states of the TRI cluster and trichothecene biosynthetic pathway, and proposed scenarios for changes in trichothecene structures during divergence of TRI cluster homologs. Together, our findings provide insight into evolutionary processes responsible for structural diversification of toxins produced by pathogenic fungiSISG received funding from the Spanish Ministry of Economy and Competitiveness (grant number MINECO-AGL2015-70671-C2-2-R). TL received funding from the National Institute of Agricultural Sciences, Rural Development Administration (grant number PJ00843203). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscrip

Effect of a high protein/low glycaemic index diet on insulin resistance in adolescents with overweight/obesity-APREVIEWrandomized clinical trial

Background Pubertal insulin resistance (IR) is associated with increased risk of type 2 diabetes mellitus development in adolescents with overweight/obesity. Objectives The PREVIEW study was a randomized parallel trial assessing the change in IR, analyzed by Homeostatic Model Assessment of IR (HOMA-IR), at 2 years after randomization to a high protein vs a moderate protein diet in adolescents with overweight/obesity. It was hypothesized that a high protein/low glycaemic index diet would be superior in reducing IR compared to a medium protein/medium GI diet, in insulin resistant adolescents with overweight or obesity. Methods Adolescents with overweight/obesity and IR from the Netherlands, United Kingdom and Spain were randomized into a moderate protein/moderate GI (15/55/30En% protein/carbohydrate/fat, GI >= 56) or high protein/low GI (25/45/30En% protein/carbohydrate/fat, GI < 50) diet. Anthropometric and cardiometabolic parameters, puberty, dietary intake and physical activity (PA) were measured and effects on HOMA-IR were analyzed. Results 126 adolescents were included in this study (13.6 +/- 2.2 years, BMI z-score 3.04 +/- 0.66, HOMA-IR 3.48 +/- 2.28, HP n = 68, MP n = 58). At 2 years, changes in protein intake were not significantly different between timepoints or intervention groups and no effects of the intervention on IR were observed. The retention rate was 39%, while no compliance to the diets was observed. Conclusions The PREVIEW study observed no effect of a high protein/low GI diet on IR in adolescents with overweight/obesity and IR because of lack of feasibility, due to insufficient retention and dietary compliance after 2 years.Peer reviewe

The center cannot hold: A Bayesian chronology for the collapse of Tiwanaku.

The timing of Tiwanaku's collapse remains contested. Here we present a generational-scale chronology of Tiwanaku using Bayesian models of 102 radiocarbon dates, including 45 unpublished dates. This chronology tracks four community practices: residing short- vs. long-term, constructing monuments, discarding decorated ceramics, and leaving human burials. Tiwanaku was founded around AD 100 and around AD 600, it became the region's principal destination for migrants. It grew into one of the Andes' first cities and became famous for its decorated ceramics, carved monoliths, and large monuments. Our Bayesian models show that monument building ended ~AD 720 (the median of the ending boundary). Around ~AD 910, burials in tombs ceased as violent deaths began, which we document for the first time in this paper. Ritualized murders are limited to the century leading up to ~AD 1020. Our clearest proxy for social networks breaking down is a precise estimate for the end of permanent residence, ~AD 1010 (970-1050, 95%). This major inflection point was followed by visitors who used the same ceramics until ~AD 1040. Temporary camps lasted until roughly ~AD 1050. These four events suggest a rapid, city-wide collapse at ~AD 1010-1050, lasting just ~20 years (0-70 years, 95%). These results suggest a cascading breakdown of community practices and social networks that were physically anchored at Tiwanaku, though visitors continued to leave informal burials for centuries. This generation-scale chronology suggests that collapse 1) took place well before reduced precipitation, hence this was not a drought-induced societal change and 2) a few resilient communities sustained some traditions at other sites, hence the chronology for the site of Tiwanaku cannot be transposed to all sites with similar material culture

Higher Protein Intake Is Not Associated with Decreased Kidney Function in Pre-Diabetic Older Adults Following a One-Year Intervention—A Preview Sub-Study

Concerns about detrimental renal effects of a high-protein intake have been raised due to an induced glomerular hyperfiltration, since this may accelerate the progression of kidney disease. The aim of this sub-study was to assess the effect of a higher intake of protein on kidney function in pre-diabetic men and women, aged 55 years and older. Analyses were based on baseline and one-year data in a sub-group of 310 participants included in the PREVIEW project (PREVention of diabetes through lifestyle Intervention and population studies in Europe and around the World). Protein intake was estimated from four-day dietary records and 24-hour urinary urea excretion. We used linear regression to assess the association between protein intake after one year of intervention and kidney function markers: creatinine clearance, estimated glomerular filtration rate (eGFR), urinary albumin/creatinine ratio (ACR), urinary urea/creatinine ratio (UCR), serum creatinine, and serum urea before and after adjustments for potential confounders. A higher protein intake was associated with a significant increase in UCR (p = 0.03) and serum urea (p = 0.05) after one year. There were no associations between increased protein intake and creatinine clearance, eGFR, ACR, or serum creatinine. We found no indication of impaired kidney function after one year with a higher protein intake in pre-diabetic older adults.Peer reviewe

Measurement of the Strong Coupling Constant from Inclusive Jet Production at the Tevatron pˉp\bar pp Collider

We report a measurement of the strong coupling constant, $\alpha_s(M_Z)$, extracted from inclusive jet production in $p\bar{p}$ collisions at $\sqrt{s}=$1800 GeV. The QCD prediction for the evolution of $\alpha_s$ with jet transverse energy $E_T$ is tested over the range 40<$E_T$<450 GeV using $E_T$ for the renormalization scale. The data show good agreement with QCD in the region below 250 GeV. In the text we discuss the data-theory comparison in the region from 250 to 450 GeV. The value of $\alpha_s$ at the mass of the $Z^0$ boson averaged over the range 40<$E_T$<250 GeV is found to be $\alpha_s(M_{Z})= 0.1178 \pm 0.0001{(\rm stat)}^{+0.0081}_{-0.0095}{\rm (exp. syst)}$. The associated theoretical uncertainties are mainly due to the choice of renormalization scale (^{+6%}_{-4%}) and input parton distribution functions (5%).Comment: 7 pages, 3 figures, using RevTeX. Submitted to Physical Review Letter

Water oxidation at hematite photoelectrodes: the role of surface states

Hematite (α-Fe2O3) constitutes one of the most promising semiconductor materials for the conversion of sunlight into chemical fuels by water splitting. Its inherent drawbacks related to the long penetration depth of light and poor charge carrier conductivity are being progressively overcome by employing nanostructuring strategies and improved catalysts. However, the physical–chemical mechanisms responsible for the photoelectrochemical performance of this material (J(V) response) are still poorly understood. In the present study we prepared thin film hematite electrodes by atomic layer deposition to study the photoelectrochemical properties of this material under water-splitting conditions. We employed impedance spectroscopy to determine the main steps involved in photocurrent production at different conditions of voltage, light intensity, and electrolyte pH. A general physical model is proposed, which includes the existence of a surface state at the semiconductor/liquid interface where holes accumulate. The strong correlation between the charging of this state with the charge transfer resistance and the photocurrent onset provides new evidence of the accumulation of holes in surface states at the semiconductor/electrolyte interface, which are responsible for water oxidation. The charging of this surface state under illumination is also related to the shift of the measured flat-band potential. These findings demonstrate the utility of impedance spectroscopy in investigations of hematite electrodes to provide key parameters of photoelectrodes with a relatively simple measurement